For internally cooled grinding disks, the cooling liquid is supplied to internal cavities in the grinding disk, from which point the cooling liquid passes at high pressure through passages to openings in the peripheral grinding surface and is outwardly discharged. The quantities of cooling liquid may be very large for large grinding disks having a diameter of 400 mm, for example. Thus, for example, such a grinding disk operating at 3000 RPM and a cooling liquid pressure of 40 to 60 bar requires approximately 200 liters of liquid per minute. However, the cooling effect of the cooling liquid is needed primarily at the grinding location at which the grinding disk contacts the workpiece to be machined. Thus, a significant quantity of cooling liquid and the associated pumping capacity are wasted. The aim is to increase the cooling power at a lower cost.
A grinding-disk shield is known and also required by regulatory requirements, so that a sector of the grinding disk is covered by a sheet-steel cover in order to prevent injuries when parts of the grinding disk or the workpiece are projected outward. These protective plates capture a portion of the emitted cooling liquid, but do not improve the cooling effect.